Primary open angle glaucoma (POAG) is treated by risk factor management for which the only modifiable risk factor is intraocular pressure (IOP). Previous physiologic studies identified the trabecular meshwork (TM) as the primary resistor to aqueous humor outflow from the eye and determined that diseased TM in POAG caused increased IOP. Simultaneously, pathology in the post-TM anterior sclera and intra-scleral distal outflow pathway has been implied with the level of disease here also being nearly equivalent to that of the TM itself. This observation coupled with recent and variably successful IOP lowering from minimally invasive glaucoma surgeries (MIGS), designed to simply bypass the TM, further confirms that IOP is more complex than just the TM. The global goal of this proposal entitled Discovery and Characterization of Anterior Sclera Pathology in Glaucoma is to identify novel, uncover the molecular mechanisms of, and realize the importance of continued impediments to aqueous humor outflow downstream of the TM in the anterior sclera and intra-scleral distal outflow pathway. In Specific Aim 1, we will apply modern histological techniques to revisit prior and rudimentary suggestions of post-TM scleral and intra-scleral outflow pathway fibrosis and collapse. In Specific Aim 2, we will evaluate the molecular mechanisms for scleral and intra-scleral distal outflow pathway fibrosis by applying knowledge regarding known pro-fibrotic agents such as TGF-b in the TM to freshly harvested glaucomatous sclera obtained during canaloplasty surgery. In Specific Aim 3, we will determine the impact of TGF-b mediated fibrosis on sclera and the intra-scleral distal outflow pathway by studying permeability characteristics via newly generated glaucoma scleral cell lines and by the development of a new animal perfusion model. This Mentored Clinical Scientist Research Career Development Award serves as a foundation and continuation of my MD/PhD completion with Dr. Solomon Snyder at the Solomon Snyder Department of Neuroscience at The Johns Hopkins University School of Medicine, ophthalmology residency training at the Doheny Eye Institute at the University of Southern California (USC), and glaucoma fellowship tutelage under Dr. Robert Weinreb at the University of California, San Diego (UCSD). I have now placed myself at USC as an Assistant Professor in Ophthalmology because USC has the track record, fresh experience with K-awardees, and excellent mentorship in Drs. David Hinton (Mentor), James Tan (Co-Mentor), and Robert Weinreb (Co-Mentor; at UCSD) to provide the additional research training and experience necessary to fuel my success. My career development plan will be built around my mentors and the Southern California Clinical and Translational Science Institute organized young investigator courses and responsible conduct in research training. Through the completion of these studies we hope to (a) further basic understanding of aqueous humor outflow from the normal eye and (b) develop an improved insight into impediments of aqueous humor outflow in POAG to allow for future innovation of pharmacological and surgical glaucoma treatments. Furthermore, through this support, I will achieve my immediate goals of developing my research program and identity as well as establish the next step in my long-term goal of becoming an independently NIH-funded glaucoma health-oriented clinician-scientist researcher.